Excavating equipment typically utilizes a bucket with a forward lip to scoop up quantities of earth for transport. A number of adapters can be removably attached to the forward lip of said bucket, while a plurality of teeth are removably attached to the adapters. To captively retain the adapter to the forward bucket lip, aligned transverse openings are formed through these interengageable elements, and a retaining mechanism is driven into these elements.
Retaining elements or locking devices for attaching the adapter to the bucket have a variety of configurations. For example, U.S. Pat. No. 4,267,653 to Hahn et al. discloses a "Locking Device for Excavating Equipment" which utilizes a clamp member, locking member, and wedge for releasably locking a slip-over adapter to the lip of a shovel dipper. The locking member is mounted in a recess in the confronting face of the clamp member. The clamp member is then installed within the aligned openings of the lip and adapter and seated against the lip. The wedge member is vertically elongated and is tapered by having a forward wall downwardly convergent relative to a rearwardly facing wall. The confronting wall is equipped with a series of crests and valleys. The locking member also includes an elongated body which in the forwardly facing portion thereof is constructed to define a plurality of cooperating crests and valleys. Bonded to the locking member is a resilient portion. As the wedge member is driven into the aligned openings adjacent to the clamp member, the crests and valleys of both the wedge member and the locking member engage. The resilient portion of the locking member is equipped with a longitudinally extending bore which enables the locking member to compress back into the cavity or recess whenever the wedge moves one-half a notch. Thereafter, the lock member moves back to its original position when the movement equals one full notch.
Likewise, U.S. Pat. No. 4,663,867 to Hahn et al. also discloses a "Locking Device for a Whisler Type Adapter" which utilizes a wedge, C-clamp lock, and a spring loaded keeper member interposed therebetween. There is no taper between the mating faces of the wedge and C-clamp. In operation, the locking device is able to move freely as the adapter moves so there is no constraint behind the C-clamp and wedge assembly. The wedge member is equipped with a ratchet adapted to engage and mate with a ratchet portion provided on the keeper member. The keeper member is also provided with a plurality of rearwardly extending ports on which the springs are mounted. The springs are also supported in countersunk openings provided in the forward face of the C-clamp. A lug is also provided on the rearward surface of the keeper member, said lug being apertured to receive a pin. The pin is slidably mounted within a horizontally extending slot provided in the side wall of the C-clamp. In sum, the system flexes with the movement of the Whisler adapter about the lip, allowing the adapter to move rather than utilize a solidly locked C-clamp and wedge system which is intended to keep the adapter tight on the lip.
A disadvantage with both Hahn et al. ('653) and Hahn et al. ('867) lies with their flexibility. With Hahn et al. ('653), to allow for the insertion of the wedge, the elastomeric element must provide a certain amount of compressibility. However, this same compressibility allows for too much vibration during operation. This vibration can lead to the ejection of the wedge. Likewise, the spring assembly in Hahn et al. ('867) tends to fail due to the amount of flex to which the system is subjected.
Therefore, a need exists for a retaining mechanism that firmly engages an adapter to the forward lip of an excavating bucket. Such a retaining mechanism should allow for easy removal of any wedge member used. Moreover, such a retaining mechanism should display only the slightest elasticity.